In a large pan, combine rhubarb, raspberries, orange zest, juice and water. Bring slowly to the boil and boil gently for 30 to 40 minutes until everything is soft and slightly thickened.
Put a small plate in the freezer to use to test setting point later. To sterilise the jars, wash 5 or 6 jars in hot soapy water then place (still wet) on a baking tray covered in foil, and put in a medium hot oven for about 20 minutes.
Add the sugar and pectin. Bring to a rolling boil and boil rapidly for 4 to 8 minutes until ready to set. Test a small amount on a chilled plate, if it wrinkles when you push it gently it's ready.
Leave to cool for 5 minutes then pour into sterile jars, top with a wax disk and seal. Leave to cool before putting in the fridge.
You could use 1kg of jam sugar instead of granulated sugar and pectin.
Amounts can be varied, I usually stick to the rule of slightly less sugar than the total weight of fruit.
Swap raspberries for blueberries, blackberries, or anything that is available at the time.
I came across this recipe when trying to find something to do with my allotment rhubarb (which i don't like). I am now on my third batch. Easy to make, exactly how the recipe states. I would definitely recommend you make this jam. - 19 May 2015